On long-duration flights, the most rational method of producing water is its regeneration from metabolic by-products of astronauts. Water is regenerated, for example, from moisture released by astronauts into the atmosphere of modules of an orbital station (or space-craft) with exhaled air and as perspiration, through the skin. Moisture is collected from the atmosphere by condensing its vapors in special apparatuses of the thermal control system of an orbital station from where the collected humidity condensate leaves together with transport air in the form of a gas-liquid mixture. The condensate contains particulates and dissolved dissociating and undissociating organic and inorganic compounds. The majority of these contaminants are toxic so that, in spite of their comparatively small concentration in condensate, production of potable water from condensate requires the removal of the contaminants.
Sorption is known in the prior art as the method of the removal of contaminants from humidity condensate by passing the condensate through a bed of activated carbon (to remove the undissociating contaminants ) and a bed of ionites (an ion exchange meterial) (to remove the dissociating contaminants) which is followed by condensate disinfection mineralization and preservation. The known method of sorption was used in a system for water recovery from humidity condensate, said system comprising a gas-liquid mixture separator, based on porous hydrophylic barriers a column with ionite and activated carbon, a water conditioning column containing salt-saturating bed materials from gypsum (CaSO.sub.4), dolomite CaMg(CO.sub.3).sub.2, fluorite (CaF.sub.2), etc., a column with an adsorbent saturated with silver salts known for a bactericidal effect (V. N. Serebryakov "Fundamentals of Designing Life-Support Systems for Spacecraft Crews". Moscow. Mashinostroyeniye. 1983, pp. 93-94).
The known method is noted for a short service life of the separator in terms of produced condensate due to clogging of pores in hydrophylic barriers with particulates and fouling of pores with microflors, the necessity for selecting the sorption bed materials (proportions of cationite, anionite and activated carbon) for each particular condensate depending on its contents of dissociating and undissociating organic contaminants, and the irregularity of mineralization and saturation of water with silver ions.
In addition, there is a method for producion of water from the atmosphere of a habitable pressurized module containing water vapors released by the inhabitants of said module, said method involving condensing said vapors into a gas-liquid mixture, filtering said mixture, separating condensate therefrom, sorption purification of condensate by passing it through activated carbon and ionites with subsequent disinfection, mineralization and preservation of the purified condensate; also known is a system realizing said method which functioned on the orbital station "Salyut-6" (A. S. Eliseyev."Techniques of Space Flights". Mashinostroyeniye. Moscow, 1983, pp. 142-145).
The system for the implementation of the known method comprises means connected in series for condensing water vapors and producing a gas-liquid mixture, a filter for said mixture, a condensate-separating unit, a unit for sorption cleaning of condensate comprising in succession chambers with activated carbon and ionite, a water conditioning unit comprising a chamber filled with sterilizer and another chamber filled with mineralizer, a contaminant carry-over sensor, and tanks for potable and service water.
The system functions as follows. A gas-liquid mixture (humidity condensate with transport air) is fed from the thermal control system of the station to the filter designed to remove particulates and partially chemical contaminants from said mixture. The chemical contaminants are removed by activated carbon while the particulates are separated by polypropylene fiber and filtering cloth.
The gas-liquid mixture then enters the separation unit where condensate its separated from transport air and fed by a pump into a purification unit containing sorption bed materials on the basis of activated carbon and ion-exchange resins, while air is returned into the service module. Condensate is separated in the separator of the separating unit comprised of a stack of capillary-porous hydrophylic tubes (porous barrier and a bladder tank outfitted with a movable piston with the intertubular space of the stack and the tank in the initial condition filled with water).
In case of potable grade quality determined with the aid of the contaminant carry-over sensor, the water from the purification unit is fed to the conditioning unit while the off-spec. water is dumped into the tank for service water. The water in the conditioning unit is saturated with mineral salts by a contact method and preserved with silver ions before entering the potable water tank.
The above-described system for water recovery from humidity condensate proved to be highly efficient on long-duration flights of the orbital station "Salyut-6" and incorporation of the filter for the gas-liquid mixture into the system made it possible to extend the service life of the separation and purification units as compared with the known system described above. However, both the recovery method used in this system and the system proper have still suffered the following disadvantages:
a short service life of the purification unit in terms of organic contaminants and its dependence on the ratio of dissociating and undissociating contaminants in the condensate; PA1 loss of permeability of the walls of the hydrophilic capillary-porous tubes in the separation unit due to fouling of pores with microflora in case of long-time intervals (a month and longer) between the filling of the unit with water during its preflight preparation and start-up and, as a consequence, reduction of its service life in terms of liquid separation; PA1 a necessity for replacing the entire separation unit after its capillary-porous tubes reach the end of their service; PA1 a lack of information on the end of service life of the separator incorporated in the separation unit; PA1 irregularity of injection of salts and ions of silver into the product water, as the conditioning unit reaches the end of its life; PA1 a relatively high specific weight of the system.